Thomas barnett



.55 outer edges of the inner mill stones.

UNITED STATES PATENT GFEICE.

THOMAS BARNETT, OF BEVERLEY, ENGLAND.

MILLSTONE.

Specification of Letters Patent No. 9,318, dated ctober 12, 1852.

To all whom it may concern:

The following is a description or specioation of t-he Improvements in Machinery for Grinding Wheat and other Grain invented by me, the undersigned, THOMAS BARNETT, of Beverley,` in the county of York, in that part of the United Kingdom of Great Britain and Ireland called England, rice miller and grocer, for which a patent under the great seal of the said United Kingdom has been granted, bearing date the eighth day of January, one thousand eight hundred and fifty-two, and for the sole use, sale, and exercise of which improvements I intend to apply for a patent privilege to the proper authorities in the United States of America.

Before describing my invention it may be proper to state that it is of consequence that wheat or other grain should be kept cool during the process of grinding. The mill stones in common use are found to deliver the flour in a heated state and also require that it should be kept until it be cool before it be passed through the dressing machine which Yoccasions a loss of warehouse room and interest on capital.

My invention not only removes the disadvantages above mentioned but also effects a 3o great saving in the power employed in the grinding of wheat or other grain which saving I estimate at from one third to one half of the power now employed in grinding with the horizontal mill stones now in ordinary use.

My invention consists in surrounding the outer edge of each of the horizontally stones hereinafter termed inner mill stones used for the purpose of grinding wheat or other grain and generally called a pair of mill stones with a concentric circular ring of stone measuring horizontally from four to seven inches from the outer to the inner edge or in proportion to the size of the inner mill stones and upon the same levels and grinding on the same plane respectively as the inner mill stones. I shall hereafter call the said concentric circular rings outer mill stones. The outer mill stones are so much larger in diameter than the inner mill stones respectively as to leave a space of from three to five inches or a space in proportion to the size of the inner mill stones between the inner edges of the outer mill stones and the stones revolve and are fed in the same manner as those now in common use. The upper mill stones (composed-of an outer and inner one) revolve at the same speed in proportion to the size and are fed in the same manner as those now commonly in use. The Linder mill stones (composed of an outer and inner one) do no-t revolve but are stationary except as hereinafter mentioned. The upper and under mill stones are of nearly the same area and diameter measured horizontally. The materials I use in the construction of all the mill stones are French bur stones or any other kind of stone suitable for grinding wheat or other grain. When I use the French bur stones I build or fix them into circular frames formed of rings of iron or other metal in such a manner that the grinding faces of the stone project from two to three inches beyond the last mentioned rings so as to allow fo-r the wearing down of the grinding face of the stone in its revolutions such frames being held together and strengthened by crossbars or flanges of metal and afterward hooping the outer circumference and then backing facing and furrowing them in the same manner as is no-w commonly used. (The diameters of the upper inner mill stone and of the lower inner mill stone should be the same or nearly the same.) The circular space between the upper mill stones and the circular space between the under mill stones ought to be of the same lor nearly the same width and be at the same relative distance from the outer and inner edges of the mill stones so that when the machinery is working the upper circular space shall be over or nearly over the under circular space.

With regard to the under mill stones the space between the outer and inner mill stones is covered throughout with wire gauze or cloth (or perforated metal plates) stretched across it near the top kof such space on a level with the bottom of the furrows in the lower mill stone and fastened by screws or otherwise to the iron frames or to wooden or metal cases made to fit the cir cular spaces such frames or cases being acted upon by screws so as to raise or lower them and also to retain them when adjusted to the desired level. I use the wire gauze or mill stones I insert brushes or sweepers or rubbers in the circular space between the outer and inner mill stones such brushes or sweepers or rubbers being as wide as the space between the outer and inner mill stones and' secured by means of grooves in the circular frame of the upper mill stones in such a manner that they may be fixed at the same or about the same angle with the furrows in the u-nder outer mill stones and be raised or depressed when required by levers springs weights or screws so as to press lightly against the wire gauze or cloth or perforated metallic plates in the under circular space and brush or sweep through such wire gauze or cloth or perforated metallic plates the completely ground flour or meal and carry forward the partially ground flour or meal toward the upper and under outer mill stones after passing between which it is discharged from the circumference of the outer mill stones more completely ground into the same kind of case as is now commonly used. I also place and fix by screws or otherwise to the upper mill stones four or more segmental wedge shaped boxes open at the wide ends and bottom and placed alternately over the concentric aperture or space through the upper mill stone and so arranged that the wide" end shall be carried forward with the mill stone against the atmospheric air and take in a current which' will prevent the partly ground flour or meal from escaping upward out of the circular spaces or apertures and also cool down the flour or meal under process the wide end of such segmental wedge shaped boxes to be three to five inches in height above t-he mill stone or such size as will admit the requisite current of air and to be furnished with slides for the purpose of decreasing or increasing the flow of air into the aperture.

Vithout particularly confining myself to the number disposition or kind of brushes sweepers or rubbers to be used I prefer to have six or eight brushes of the width of the circular space of a similar kind and with bristles of the same strength fixed in wood as are now commonly used in cylinders for dressing flour. I prefer that each brush or sweeper shall have its wooden or other stock or upper part made of such a size that together with the bristles or other sweeping surface it shall extend from near the top to the bottom of the circular space between the two upper mill stones in such a manner that such brush or sweeper shall by the rotation of the revolving mill stones act as a fan and displace the air and cause thereby a current of air which current has a tendency to cool the partially ground flour or meal on its passage to the outer mill stones for further grinding. With regard to the respective proportions of the inner and outer mill stones to each other I do not confine myself to any exact proportions but I prefer that the inner and outer mill stones shall contain about the same area of grinding surface respectively and with regard to the respective proportions of the area of the circular aperture between the inner and outer mill stones and the area of the inner and outer mill stones themselves I do not confine myself to any exact proportions but I prefer that the said circular apertures should each contain from one third to one fourth part of t-he area of the inner under mill stone. I allow the whole of the flour or meal as fast as it .is produced to fall into a circular hopper placed underneath the mill stones and terminating in one or more spouts. The hopper which receives the flour or meal is made of wood iron or other 'metal and is of a somewhat conical shape and the diameter of it is about five or six inches greater than the diameter of the outer lower mill stone.

In using blue stones or grey stones or any other kind of stones which are found in one piece instead of having a frame to hold them together as before mentioned portions of the stone itself may be left at intervals in the circular space to hold together the outer and inner portions of the stone so as to leave segments of circular rings for the openings in the under and upper stones or the inner and outer mill stones may be placed in rings as before described for French bur stones. Vhere this is done all that I have before said as to the fixing of the brushes or sweepers and wire gauze or perforated metal plates and covers with respect to outer and inner mill stones will apply to the outer and inner portions of the mill stones consisting of one piece only.

I have found it advantageous in grinding tender or damp wheat or other grain to surround the outer millstones with second outer mill stones with circular spaces like those above described between them and the first outer mill stones in which last mentioned circular spaces I place brushes or sweepers and wire gauze or cloth or perforated metallic plates and covers in the same manner as in the first mentioned circular spaces.

My improvements are applicable to all pairs of mill stones grinding wheat or other grain and worked horizontally whether moved by steam wind water horse or any other power.

The several parts of my improvements in machinery for grinding wheat and other grain are shown in the accompanying drawings the letters in which refer to the same parts.

The feeding hopper gearin and feeding apparatus are not any part o my improvements but are in the ordinary form and so well known as not to require further description but are shown in section in Figure 8.

Fig. l plan and Fig. 2 section of the circular frame for receiving and retaining the French bur stones or other stone and also the brushes and the wire gauze in which plan A is the eye of the stone A1 inner stone space, A2, circular space forl wire gauze or brushes. Fig. 3. Plan of the working face of the under mill stones in which C is the inner under mill stone D, is the wire gauze F is the outer under mill stone. Fig. 4. Plan of-upper mill stones in which A is the eye of the stone B is the inner upper stone G are the brushes and F is the outer upper stone. Fig. 5, is a plan of the working face of blue or gray mill stones with segmental apertures in which C is the under inner mill stone, D the wire gauze and E is the under youter mill stone. Fig. 6 plan of upper mill stone in which A is the eye of the stone B is the inner upper stone G the brushes and E the outer upper stone. Fig. 7 shows a section of mill in which A is the eye of the upper mill stone B is the inner part of the upper mill stone C the inner part of under mill stone D is the wire gauze E the outer part of the under mill stone F the outer part of the upper mill stone G the bushes H the segmental wedge shaped boxes T1, the casting for receiving and retaining the bottom stone which casting is made so A much larger in diameter as to leave an open space of two or three inches between the inner part of the casting and the outer edge of the stone which allows the flour to drop from the outer circumference of the stones into the hopper U along with that partof the flour discharged from the wire gauze.

I am aware that holes or apertures in upper and under mill stones have been some time in use and I do not claim simply the making of holes or apertures in mill stones as my invention but The making in under mill stones of holes or apertures covered with wire gauze cloth perforated metal plates or any other substance that will allow part of the meal to pass through after it is sufficiently ground in combination with holes or apertures in upper mill stones containing sweepers brushes or rubbers for the purpose of sweeping rubbing or brushing the meal over or through the wire gauze cloth perforated metal plates or other substances without confining myself to the exact details described in the above specification.

As witness my hand and seal at the borough of Kingston upon Hull in England aforesaid this thirtieth day of April one thousand eight hundred and fifty-two.

THOMAS BARNETT. [L. s]

Signed by the within named Thomas Barnett in the presence of JNO. BLYME ROBINSON, HY. FRS. SKEET. 

